mocabe



April 18, 1933. MCCABE 1,904,378

CONSTANT CURRENT IGNITION DEVICE Filed May 9, 1930 3 Sheets-Sheet 1 INVENTOR N BY RA E [li CABE ATTORNEY 9 Apnl 18, 1930. L E. MOCABE 1,904,378

CONSTANT CURRENT IGNITION DEVICE Filed May 9, 1930 3 Sheets-Sheet 2 J9 I I X WJ M ATTORN EY April 18, 1933.

1:; i liiiaw'inlli' um "i a @m! m mun ii lll' l'rl l BTE IIIIE INVENTPR Patented A r. Is, 1933 PATENT OFFICE m a. means, or cmcaco, minors CUB-mil! iemron DIVIGE Application fled m a, 1930. Serial No. 451,187.

This invention relates to improvements in ignition devices for fluid fuel burner mechanlsms and more particularly to a current ignition device for a hot wire ignition system.

Not only does the commercial voltage fluctuate in the same locality but the commercial voltage varies in different localities. A hot wire i 'tion for fluid fuel burners 1 includes an ectrical resistance element adapted to be heated to incandescency by the commercial current to ignite the fluid fuel.

Constantcurrent transformers have been included in the ignition circuit to insure the passage of a constant current thro h the resistance element irrespective of the uctuations or variations in commercial lines.

It is an object of this invention to prov de such a constant current ignition system with 2 means whereby should the resistance 1gmtion element by any cause become destroyed or inoperative thereafter upon an imtial start fuel cannot be supplied to the burner. In all hot wire ignition systems for fluid fuel burners it is necessary to first bring the resistance ignition element to incandescency before fuel is supplied. This preliminary heating period is called in the trade preheating. Difierent types of burners require 80 pre-heating periods of different duration, so that variations in the pre-heating period may cause the mechanism to become inoperative or may cause dangerous results such as delayed ignition. It is a further object to provide means, when once adjusted to the particular burner, to produce a constant preheating period irrespective of fluctuations or variations in the commercial current.

ence is made to the accompanying sheets of drawings which illustrate a preferred form of this invention with the understanding that minor detail changes may be made without departing from the scope thereof.

With these and other objects in view, refer- In the drawings: Figure 1 is a view illustrating a stack switch mechanism in front elevation with a constant current transformer and parts actuated thereby in diagram with a wiring diagram showing the electrical connections to the various parts of a fluid fuel burner system.

Figure 2 is an enlarged detail view of the constant current transformer panel in front elevation with parts actuated thereby shown a in central vertical section and the cover in section. v V

v Figure 3 is a view in side elevation of Figure 2 with the cover on one side shown in section.

While it is preferable to employ the stack switch illustrated on the panel 1 any stack switch which upon the establishment of combustion will close the motor circuit before the ignition circuit is broken will suflice. The particular stack switch illustrated in this embodiment of this invention is a commercial article and is fully disclosed in this applicants prior copending application, Serial No. 418,684, filed January 6, 1930, and includes an ignition switch 2'and a switch 3 in the running motor circuit which are shown in the normal position assumed when the burner mechanism is idle, that is, with the ignition switch 2 closed and the motor running switch 3 open. The normal operation of this stack switch mechanism causes the motor running switch 3 to close before the 'gnition switch opens after the establishment of combustion.

. A constant current transformer is mounted on the panel 4 having a moveable or floatof an electrical resistance igniter element 8, the other terminal of which is connected in circuit with the other pole of the secondary coil 6.

A starting motor switch 9 is mounted above the solenoid which normally assumes the open position when the solenoid is deenergized. The core 10 of the-solenoid preferably mounts at its lower end the piston 11 in the dash pot 12 secured upon the under side of the solenoid which is adjustable to limit the time of movement of the core 10 in arriving at the upward end of its movement when the solenoid is energized. The upward movement of the core 10 acts, preferably through shaft 13, to close the starting motor switch 9 and maintain it in closed position as long as the solenoid remains energized.

The manner in which the destruction of the ignition element will thereafter prevent the initial supply of fuel and the manner in which the pre-heatmg period is maintained constant will be more readily understood by following the circuits shown on the wiring diagram on Figure 1. As previousl stated, when the burner mechanism is idle t e ignition switch 2 is normally in closed position and the starting motor switch'9 and running motor switch 3 are normally in the open position, as shown on Figure 1. The incoming commercial our- 1 rent travels through wire 14 passing through the room thermostat T and boiler control B to the binding post 15 and from there to the other end of the winding conveys the current through wire 20 through binding post 21 back to the commercial line.

The energizing of the primary coil 5 induces a current of constant intensity in the winding of the secondary coil 6, so that this constant current is conveyed from one end of the winding of the secondary coil 6 throu h wire 22 to one end of the winding 7 of t e solenoid and from thence through wire 23 through the resistance ignition element 8 back to the other end of the windin of the secondary coil 6. The energizing o the solenoid by the passage of this constant current through its winding 7 imparts an upward tem, because the constant current from the secondary coil 6 will always pass with the same constant intensity through the windings of the solenoid, irrespective of the fluctuations or variations of the commercial voltage.

The closing of the starting motor circuit causes the incoming current which passes through the closed safety switch S to the binding post 17 to branch so that part of it passes therefrom through wire 24 to binding post 25 and fromthence through the closed starting motor switch 9 to binding post 26- and from thence to binding post 27 and from there to binding post 28, passing through the release mechanism of the safety switch to binding post 29 and from there to the binding post 30 and from this binding post to the The pre-heating period occurs between the initi closure of the thermostat and the closing of the starting motor switch 9. The closing of the-motor starting switch starts the motor which supplies fluid fuel to the burner mechanism a ter the ignition element 8 has been heated to incandescency. Combustion then normally takes place. It is readily seen that should the resistance ignition element 8 be inoperative or be destroyed for any cause, the secondary circuit through the secondary coil 6 of the transformer will not be completed and therefore the windings 7 of the solenoid will not be energized and the starting-motor switch will therefore remain in its normal open position so that the burner mechanism motor M cannot be started until the ignition element has been replaced or repaired.

As above stated, the starting of the burner mechanism motor normally initiates combustion. The stack switch mechanism responds to the establishment of combustion and as described in this applicants said prior application, the runnin motor circuit switch 3 is closed and therea ter the ignition switch 2 is opened. The closing of the running motorswitch 3 closes a circuit so that the incoming current passing through safety switch S to the binding post 17 passes by way of wire 31 through the closed running motor switch 3 to binding post 29 andfrom thence through wire 24 to binding post 30 to the burner mechanism motorM. This is called the running circuit because as long as combustion con the running motor switch 3 will remain closed. After this running circuit is closed the ignition switch 2 is opened so that coil 5 of the constant current transformer,

whereuponthe secondary coil 6 is also deenergized and thereafter the solenoid 7 is likewise deenergized'and'as-the core 10 descends the starting motor switch 9 assumesv its normal open position.

The normal operation of the room thermostat will eventually open the running circuit of the motor, and after the discontinuance of combustion, the stack switch will return to its normal idle position in which the ignition switch 2 will assume its closed posi-- tion while the running motor switch:3 will an electrically controlled fluid fuel burner assume its open position and the system be ready to again initiate combustion when the room thermostat is closed.

It is readily seen that this construction not only prevents initial starting of the burner m'echanism motor in case the ignition element is inoperative but also provides in the normal operation a constant pre-heating period of the ignition device, irrespective of the fluctuations or variations in the commercial current.

- tion returnsthe running motor switch 3 to Should for anyreason, while the burner mechanism is operating normally after the room thermostat has closed, the flame fail then the stack switch responsive to combus- 7 open position thereby breaking the circuit through the holding magnet H. As described in said prior copending application, the tie-energizing of the holding magnet H will release the ignition switch 2, allowing it to return to the closed position. If the room therefore the circuit closed through the starting motor switch 9 passes through the binding post 28, and throughthe release mechanism of the safety switch to binding. post 29, whereby after a predetermined time the safety switch S is released and breaks the motor circuit, causing a complete shut-down and requiring a manual reset before operation can be resumed.

What I claim is:

1. In an electrically controlled fluid fuel burner mechanism, a hot wire ignition system including an electrical resistance igniting element, a constant current transformer, means for energizing the primary coil of the transformer, means connecting the igniting element in circuit with' the secondary coil, an electro-magnetic means interposed in the 2 which.

secondary circuit, and means actuated by the energization of the'solenoid to su ply fluid fuel to the igniting element, where y a break 1 in the secondary circuitprevents the supply of fuel to the burner.

2. In an electrically controlled fluid fuel burner mechanism, a hot wire ignition system including an electrical resistance igniting element, a constant current transformer, means for energizing the primary coil of the transformer, means connecting the igniting elementin circuit with the secondary coil, an

electro-magneticmeans interposed in the secondary circuit, and means actuated thereby a constant predetermined time after each energization of the primary coil to supply fluid fuel to the igniting device, thereby insuring a constantpre-heating period of the p igniting device.

3. A constant current ignition device for mechanism including a constant current transformer, means for closing and. opening .thecircuit to the primary coil thereof, an electrical resistance igniting element and asolenoid interposed in the secondary circuit of the transformer, means for opening and closing the circuit to the fuel supply means actuated by the solenoid to close said circuit to supply fuel to the igniting element a predetermined time after each energizing of the secondary circuit of the transformer.

4;. A constant current ignitiondevice for a hot wire ignition system of an electrically controlled fluid fuel burner mechanism including a constant current transformer and a switch in the control system adapted to connect-the primary coil of the transformer to the source of electricity, an electrical resistance igniting element and a solenoid interposed in the secondary circuit of the transformer, and a normally open switch actuated by the energization of the solenoidto close a circuit between the source of electricity and fuel supply means to supply a predetermined time after each energizing of the secondary circuit, fluid fuel to the incandescent igniting element, thereby insuring a constant pre-heating of the igniting element previous to the initial supply of fuel.

a hot wire ignition system of an electrically controlled fluid fuel burner mechanism including in the control thereof a switch mechanism responsive to the establishment of combustion, a constant. current transformer, an electrical resistance 1gn1t1ng element and a solenoid in the secondary circuit 5. A constant current ignition device for solenoid to close a circuit from said first switch to initiate the supply of fuel to the igniting element and a. switch in said switch mechanism normally open in a circuit from the source of electricity to the fuel supply means, said switch mechanism upon establishment of combustion first closing the switch to maintain the circuit from the source to the fuel supply meansv and then opening the switch in the transformer circuit, whereby upon each closing of the'circuit to the control the supply of fuel is initiated after a constant pro-heating of the ignition element and thereafter the fuel supply is maintained after the transformer is deener 'zed.

IRA E. cCABE. 

